Synchro-tie for ship propulsion



April 1938. w. SCHAELCHLIN 2,114,859

SYNCHRO-TIE FOR SHIP PROPULSION Filed June 30, 1936 /7 8 l3 l4 WITNESSES: 7 INVENTOR 26* Wirer ZJL- /Ch/m. j a! Wm M W ATTORNEY Patented Apr. 19, 1938 I 2,1

UNITED STATES PATENT OFFICE SYNCHRO-TIE FOR SHIP PROPULSION Walter Schaelchlin, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation Pennsylvania Application June 30, 1936, Serial No. 88,102

'i 1 Claim. (Cl. 172293) This'invention relates to the control of operamatically effecting synchronous out-of-phase or, tion of two or more machine elements, and more if desired, in-p'hase, operation of a pair of shafts. particularly relates to a system of control for Referring to Fig. 1, the reference characters maintaining two or more shafts in a predeterl and 2 designate prime movers. These prime mined relationship during synchronous operation. movers may be Diese engines, reciprocating In a system where two or more shafts are opsteam engines, or turbines, as shown. The turerated by p me movers having periodically varybines shown have the conventional governor coning driving torques, as Diesel engines or any reciptrolled intake Valves 3 d 4 and e their rocating engines have, and also where the driven Shafts 5 and 5 mechanically coupled to e p oshafts operate loads, such as pumps or propellers, Pellers T and 8 through transmission gearing 9 10 that have a periodically varying characteristic, and mi vibrations are easily set up between the moving A Synchronous generator H is mechanically parts and the building t u t or fou datio coupled to the propeller l and thus generates an Such vibrations, id from being very annoying, alternating current having a frequency that is a may give rise to resonance and thus endanger the meesur e of the speed of Propeller 15 ioundation and i t, A synchronous generator I2 is mechanically On board ship, u h resonance is especially coupled to the propeller B and thus generates an noying as w ll s dangerous. The tendency to alternating current having a frequency that is produce vibrations on board ship is especially a measure of the Speed of the propeller i great because the moving parts are heavy and A suitable source of direct current, evidenced the load changes rather pronounced relative the by the buses and H provides direct current foundation, o frame Structure; the propeller excitation to the field windings I5 and N5 of the blades, if operating in synchronism and synchronous generators II and I2. The energizphase, cause a reciprocating force to act on the ing circuit may be tweed from bus thr 011311 2:) Ship; and, on Diesel engine operated Ships, or conductor ILfield wind ng I5 fromthe upper ter- 5 for that matt on ships using any reciprocating nnnal to the lower terminaL'field winding l6 from engine, the prime movers cause reciprocating the lower terminal to the upper terminal and forces t t on t shin conductor IE to the bus l4. Since the field One object of this invention is to provide for windings m are eonnectee in Series and maintainin a selected phase relation between have the wmdings on corresponding pole pieces 30 two or mo d i operatin synchronousiy connected for opposite polarities the alternating Another object of this invention is to provide currents generated by h generators H and I: i for electrically maintaining two or more shafts for a two pole machme at the same in any selected relationship during synchronous quency and in phase electncany when cone o r ti sponding pole pieces of the generators are out-of- A still further object of this invention is to pro- Phase mechanicallyvide means for automatically selecting and main- To indicate Such eutof'mechamcal'phase positaining synchronous out-of-phase operation of a tion of correspondmg pole pleces of the two P plurality of sh ft generators H and I2, the armature windings I9 40 It is also an object of this invention to provide and are interconnected respectively with the 0 for'automatically selecting and maintaining synactuating coils and 22 of a Well known chronous in-phase operation of a plurality f chroscope S. The core structure for coil 22, which shafts. v is the movable coil, is provided with a pointer P Other objects and advantages will become more adapted to whet with a Stationary mark apparent from a study of the following specificawhen the genera-tors H and during Operation, 45 tion when considered with the accompanying are not Operating at exactly the ame p d, t drawing, in which; pointer P will rotate and its direction of rotation Figure 1 is a diagrammatic showing of an will be determined by the generator having the bodiment of this invention, illustrating manually greater p W t rat s H and 2 operable means for effecting the synchronous r t e at exa t y h Same speed the tern 60 operation of a pair of shafts s as t keep a current generated by the generators will have the selected relative position during such operation; am frequency and Will be P The y and chroscope S will thus indicate synchronous 0p- Fig. 2 is a diagrammatic showingof a modificaeration of the generators because the pointer P tion of this invention, illustrating means for autowill be stationary opposite stationary mark M. 55

When the pointer P becomes stationary or substantially stationary opposite the mark M, corresponding pole pieces will be out-of-mechanicalphase. In ship propulsion systems it is desirable that corresponding points on corresponding propeller blades move toward the hull at the same instant and away from the hull at the same instant. This means that the water will be thrown against the hull at both sides at the same time. Looking toward the propellers from the stem, the propellers will be seen to rotate in opposite directions. By means of the synchroscope not only is synchronous operation indicated but a predetermined relationship between the propeller blades is indicated.

The mechanical interconnection of the rotors of the generators H and I2 with the respective propellers I and 8 is preferably such that the synchroscope will indicate, when pointer P is opposite mark M, in-phase operation of the propellers but out-of-mechanical-phase operation of the prime movers.

If, at the instant the propellers are mechanically in phase position, means were provided for maintaining such relation regardless of speed variations of the propellers, resonance can be eliminated. Resonance will not occur because none of the vibrating or oscillating parts of the entire system will have the same direction of motion at the same time.

This invention provides for substantially locking the propellers in any selected phase position. Such operation is accomplished by the proper control of two synchronous generators mechanically coupled directly to the propellers. These generators 23 and 24 have their rotating armature windings connected directly to each other. Any non-synchronous operation of the generators, when the field windings 25 and 26 are energized, will cause heavy circulating currents to flow in the armatures of the two generators. A heavy torque is thus produced on the propellers to prevent them from taking any other relative position than the position determined by the generators 23 and 24.

To establish the controlling interconnection of generators 23 and 24 the attendant watches the pointer P of the synchroscope and when the pointer P is opposite the mark M and substantially stationary, he actuates the push button switch 21. lishes a circuit from bus I 3 through conductors l1 and 28, switch 21, actuating'coil 29 of the field contactor 30, contact members 3i of the overload control relay 33, and stop push button 32 to the bus l4. The field windings 25 and 26 are thus energized from buses l3 and 14 by the operation of the field contactor 30. The circuit may be traced from bus l3 through conductor H, the field winding 25, contact members 34 of the field contactor 30, field winding 26, and conductor l8 to bus l4. The field windings 25 and 26 thus become energized at a time when the propellers are mechanically in phase position and the generators, as long as there is no tendency for the propellers to become displaced will operate at noload.

If propeller 1 tends to lag or pull out of its positional relationship to shaft 8, the dynamo-electric machine 23 becomes a motor and dynamoelectric machine 24 becomes a generator. The speed of propeller I is thus increased and the speed of propeller 8 is decreased. Synchronous operation of the propellers is thus maintained and also the phase relation is maintained,

Operation of this switch 21 estab-' In Fig. 2 a modification is shown for automatically accomplishing the novel results hereinbefore discussed. For the same elements the same reference characters used in Fig. l are applied and different reference characters are only used for elements that are' distinctly different.

Instead of using a push button switch that is to be operated by the attendant when the synchroscope indicates synchronous in-phase operation of the propellers, the synchroscope can be operatively so related to the field contactor 30 that the field windings 25 and 26 are automatically energized when the proper position obtains between propellers l and 8.

In the modification shown in Fig. 2 all the elements function exactly as described in connection with Fig. 1 except that the control of the field contactor 30 is automatic. Assuming that the propellers 1 and 8 are to be brought in the desired operating relation. In such case one prime mover may be caused to operate at normal speed whereas the other is made to vary its speed to search for the proper operating conditions. When the two propellers are in the correct position the cam 40, which is mounted to operate like pointer P, slows down and the notch 4| is brought in position so that roller 42' drops into the notch and, since the operating conditions are nearly right, roller 42 will remain in the nohh 4| long enough so that the field contactor 30 is caused to operate.

The roller 42 is mounted on the spring biased pivoted lever 43 and when the roller 42 rests in notch 4!, contact members 44 are engaged. A circuit is thus established from bus l3 through conductor I], contact members 44, conductor 45, actuating coil 29 of field contactor 30, contact members 31 of overload control relay 33 and stop push button switch 32 to the bus l4. The field windings 25 and 26 are thus automatically energized at the proper instant and the propellers will thereafter operate in synchronism but mechanically in an in-phase position.

Operation of the field contactor 30 causes the closing of contact members 35 whereupon a holding circuit is established for the actuating coil 29 and field contactor thus remains in its operated position independent of the position of push button switch 21, or contact members 44, depending on whether manual or automatic control is used.

When the propellers tend to pull out of their predetermined relative position heavy circulating currents flow in the armatures of the dynamo-electric machines 23 and 24 with the result that contact members 3k are opened. The field windings 25 and 26 are thus deenergized and the controlled operation of the propellers stops. Operation of stop push buttons 32 will similarly stop the controlled operation of the propellers.

The embodiment and the modification hereinbefore described and shown in Figs. 1 and 2 respectively are thought to be merely illustrative of this invention. Because others skilled in the art, particularly after having had the benefit 0f the teachings of this invention, can readily devise other circuit diagrams and other modifications for accomplishing the novel results of this invention. This invention is, therefore, not to be limited to the specific showings made, but is only to be limited by pertinent prior art and the appended claim.

I claim as my invention:

In a system of control for controlling the operation of a pair of shafts, in combination, a prime mover mechanically'coupled to one of the shafts for driving the same, a second prime mover mechanically coupled to the other of said shafts for driving the same, a pair of electric generators coupled to the respective shafts and each having armature windings adapted to generate alternating currents, the frequencies of which are proportional to the speeds of the respective shafts, field windings for each of said generators mounted on the rotating elements of the generator, a source of direct-current electric energy, said field windings of the respective generators being so connected to the source of direct-current energy that corresponding pole pieces for the field windings of the respective generators are of opposite polarity and the rotating elements of the generators will, therefore, be in an out-of-mechanical phase position when the currents generated in the armature windings of the two generators are of the same frequency and in phase electrically, a synchroscope having a pair of windings connected to said respective armature windings of said generators adapted to indicate when the currents generated in the armature windings of the generators are of the same frequency and in phase electrically, a pair of synchronous dynamoelectric machines having their rotating elements coupled to two shafts mechanically coupled, respectively, to said pair of shafts and having their armature windings interconnected and mounted on the rotating elements thereof, said dynamo electric machines having field windings on the stationary elements of the respective dynamo electric machines, and means responsive to the operation of said synchroscope adapted to energize said field windings of said dynamo-electric machines at an instant when said first-mentioned pair of shafts are in an out-of-mechanical phase position.

WALTER SCHAELCHLIN. 

